240 



DESCRIPTIONS OF THIETY-THREE NEW SPECIES OF GASTROPODA 

 FROM THE PERSIAN GULF, GULF OF OMAN, AND NORTH 

 ARABIAN SEA. 



Ey Jamks Cosmo Melvill, M.A., D.Sc. 

 Bead 14th June, 1912. 

 PLATES XI, XII. 

 In continuation of the last paper upon the subject,' I now bepr to 

 offer descriptions of some more interesting MoUusca, mostly culled 

 from the almost inexhaustible supply forwarded by ^Ir. F. W. 

 Townsend from time to time, one or two being added from Bombay, 

 where they were obtained either by the same collector or Mr. Alexander 

 Abercrombie. The opportunity has also been embraced of retiguring 

 two or thi'ee species, e.g. Ethalia diotrephes, Melr. (^vide PI. XI, 

 Pigs. 17, 17rt), which, till lately, was only known by the type, a poor 

 and broken example. In this new delineation the elaborate sculpture 

 and curious form of this little species are shown much more distinctly. 

 Argyropeza divina, M. & St., too, is now figured from an adult 

 example for com])arison with A. Schepmnniana, described in this 

 paper. And, thirdly, Mcmgilia recta, Smith, an interesting Persian 

 Gulf species, has never till now been represented by any figure : tiiis 

 omission is now rectified. 



CoccL'LixA siiiPLiciOR, n.sp. PI. XII, Figs. 1, \a. 



C. testa pax'va, ovato-conica, compressa, Itevi, albo-lactea, sub- 

 pellucida, tenui, lateribus fere parallelis, utrinque rotundatis, planius- 

 culis, superficie omni nitida, sub lente lineis obscuris incrementalibus 

 concentrice praedita, apice acuminato, nucleo loevi, perinconspicuo, 

 sub lente globose, vitreo, postice arcuato-inelinante, antice cojivexiore, 

 intus alba, perliievi. Long. 2'7o, lat. 1, alt. I'oOmm. 



ITab. — Gnli of Oman. Lat. 24= 58' N. ; long. 56'' 54' E. ; 156 

 fatlioms, in shell-sand. 



This is, curious to relate, the first Cocculina reported from these 

 dredging results ; and even this has occurred very rarely. All the 

 examples seen are unfortunately dead, and consequently it has been 

 impossible to examine the radula. It is a very minute, laterally 

 parallely-corapressed species, perfectly smooth save for very microscopic 

 concentric incremental growth -lines, whole substance papyraceous 

 and most fragile. It is to be n^ted that Dr. Schepman - treats of no 

 less than seven new species of this genus, mostly dredged in live 

 condition, in the accoimt of the Prosobranchiata of the Siboga 

 Expedition ; and Dr. Dall,^ the author of the genus, of three in the 

 reports of the U.S. ss. Albatross cruise. 



' Ann. Map;. Nat. Hist. (8), vol. vi, pp. 1-17, pis., 1910. 



- Prosobr. Siboga Exped., pp. 17-22, pi. i, figs. 4-10 ; pi. viii, figs. 8-12, 1908. 



^ Mull. Mus. Comp. Zool. Harvard, xliii, pp. 340, 341, pi. xvi, figs. 3-7, 1908. 



